1. Field of the Invention
The present invention relates to a door for a vehicle, the rigidity of which is high.
Further, the present invention relates to a door for a vehicle, the rigidity and the buffer action property of which are high.
2. Discussion of Background Art
As a conventional door for a vehicle, the rigidity of which is high and the weight of which is light, a door frame structure is well known (For example, refer to Patent Document 1.). This door frame structure includes: a front frame member (a door inner front member) for forming a front edge of the door body; a rear frame member (a door inner rear member) for forming a rear edge of the door body; an upper frame (a waist reinforcing member) for connecting the front frame member with the rear frame member; and a lower frame (a sill extruded member).
The lower frame (the sill extruded member) in this door frame structure is made by a plate-shaped member made of light metal such as aluminum or magnesium. Alternatively, the lower frame in this door frame structure is made by a plate-shaped member of an extruded material of light metal. The lower frame (the sill extruded member) is arranged being extended in the longitudinal direction of the vehicle body with respect to the door body.
[Patent Document]
JP-A-2001-341529 (Pages 4 and 6, FIGS. 1 and 17)
Further, concerning the conventional door for a vehicle, the rigidity of which is high, a reinforcing structure of the door for a vehicle is well known, in which an inner frame (an inner reinforcement) extending in the longitudinal direction is arranged in an upper portion of the door body so as to ensure the mechanical strength of an upper portion of the door body. Concerning this reinforcing structure, for example, refer to Patent Document 2.
This reinforcing structure of the door for a vehicle includes: an outer reinforcement arranged in an upper end portion of the outer door panel; and an inner reinforcement arranged in an upper portion of the inner door panel. Each of the outer and the inner reinforcement is a cylindrical member having a closed cross section. These outer and the inner reinforcements are made of an extruded material of light metal such as aluminum.
The inner frame (a waist reinforcing member) of this door frame structure includes an inner waist reinforcement and outer waist reinforcement. Each of the inner waist reinforcement and outer waist reinforcement is a substantially cylindrical body, the cross-section of which is hollow, made of an extruded material of light metal such as aluminum.
[Patent Document 2]
JP-A-2001-334955 (Pages 4 and 5, FIGS. 3 and 4)
However, in the case of the door structure for a vehicle described in Patent Document 1, the following problems may be encountered. Concerning the door body, it is impossible to ensure a sufficiently high rigidity of the lower portion of the door body only by the lower frame (the sill extruded member). Therefore, it is necessary to reinforce the lower portion of the door body by arranging a side guard bar in the central portion of the door body and in the neighborhood of the lower frame (the sill extrusion member).
Especially, in the case of a door for a vehicle, the weight of which is reduced, in order to take countermeasures against a car collision, it is desired that the mechanical strength of the lower portion of the door body is high.
Further, in the case of the inner reinforcement arranged inside the vehicle described in Patent Document 2, the following problems may be encountered. In order to ensure the rigidity of the door, the inner reinforcement has a relatively large cross section. Therefore, the thickness of the entire door is increased.
In the case of the inner reinforcement and inner waist reinforcement arranged inside the vehicle described in Patent Document 2, the following problems may be encountered. In order to ensure the rigidity, the cross section is formed into a closed section having a hollow portion. Therefore, in the case where a passenger bumps against the inner reinforcement and inner waist reinforcement when the vehicle comes into a collision with another one, since the inner reinforcement and inner waist reinforcement have a cylindrical hollow portion, it is difficult for the inner reinforcement and inner waist reinforcement to be deformed.
It is desired that the inner frame, which is arranged in the door body inside the vehicle, is provided with both the rigidity for reinforcing the door body and the buffer action property for protecting the passenger from an impact force generated in a collision.